The invention relates in general to the field of printed circuit boards, or PCBs, integrated circuit packages and assemblies, as well as methods of fabrication thereof. It is, in particular, directed to dense integrated circuit packages and assemblies using integrated circuit chips mounted on PCBs using edge soldering.
Printed circuit boards are used to support and electrically connect various electronic components. PCBs use conductive tracks and contact pads, which are typically etched from a copper sheet laminated onto a non-conductive substrate (typically a FR-4 glass epoxy). PCBs can be single sided or double sided. One also knows multi-layer PCBs, which allow for higher component density.
With ever higher integration and higher speed of microprocessors and memory compact packaging is of high importance, in particular the reduction of wire length between devices. High density interconnect boards have been proposed, which comprise blind and/or buried vias and offer higher circuitry density than traditional circuit boards. Beside, rectangular assembly of PCBs exploit the third dimension, allowing PCBs (or IC packages comprising PCBs) to be placed close to each other. PCBs may for instance be grouped in horizontal or vertical arrangements using sockets to maintain and electrically connect them to, e.g., a base board.